The present invention relates generally to tandem axles of semi trucks, and is particularly concerned with a lock pin release device for assisting in release of the lock pin of a tandem axle to permit adjustment of the position of the tandem wheels of the trailer depending on the load.
The tandem wheels of a semi truck trailer are releasably secured in position by means of oppositely directed lock pins engaging in any one of a series of openings in the trailer frame. The lock pins are linked to the tandem axle. The wheels often have to be moved to a different position to provide the best support depending on the load distribution in the trailer. The tandem axle must be released in order to re-position the wheels. The tandem axle lock pins are normally released manually by the driver pulling on a release rod which is linked to the two lock pins by means of a modified bell crank arrangement. It can be very difficult for the driver to pull out the release rod manually, particularly when the lock pins are not properly aligned in the respective frame openings. The driver may return to the truck cab and move the truck slightly in order to attempt to center the lock pins better. After each movement, the driver must return to the release rod and attempt to pull it again, unless a second person is available to pull the rod after each movement of the truck. Thus, it may take the driver 30 minutes or more to re-position the tandem wheels.